Just got the model above, and, for my surprise, it seems it lacks rSAP. This model sold in Brazil is an hybrid dual SIM.

Looking at the "system informations" in my MacBook, when I pair the S8+ with the Mac, I can see the "SIM access" service is missing in the bluetooth services, while in my former S7 Edge the "SIM access" service is there - never had an issue in my car multimedia with the S7, as the media always used the SIM card data package in the S7 to get access to internet. However, the car is not able to access the SIM in the S8+.

Yes. The non-plus S8 is currently my personal phone, unrooted (= without my app ) and still supports rSAP without problems. Samsung also reliably lists rSAP/SAP support in their technical specifications.